Air humidification apparatus

ABSTRACT

A movable device for improving the indoor air-environment comprising a water pump, a substantially vertical sheet element (10, 11, 12) which is so arranged that a free falling curtain-like stream of water (17) is formed at the upper end of the sheet element proximate to the sheet element (10, 11, 12) and a tank (9) for collecting and recirculating the water to the water pump. A satisfactory air humidification and an effective removal of impurities in the air are obtained.

The present invention relates to a device for improving indoorair-environment and in particular for providing a suitable airhumidification and absorption of undesired substances as wall ascreating a pleasant sight and sound environment, which device comprisesa wall and a water pump connected to means for forming a curtain-likestream of water at the upper end of the wall, and a tank located at thelower end of the wall for collecting and recirculating the water to thewater pump.

Concurrently with the increasing use of electric appliances and machinesin offices and shop premises, major problems of maintaining a healthyand pleasant indoor air-environment in such premises have emerged. Theproblems are far more pronounced in computer rooms in which largecomputers are installed which are to operate 24 hours a day, and fromwhich large amounts of air and heat are emitted.

Combined with a greater understanding of the problems facing i.a.allergic subjects this has created a great need for developing deviceswhich can effectively influence the indoor air-environment.

It is known to influence the indoor air-environment by installingcentral air-condition systems which serve to provide a suitable renewalof air in the rooms connected to the system and to ensure that the roomair has a suitable temperature and humidity.

This is effected by means of a system of air channels which are oftenmounted covered and therefore difficult to gain access to, therebymaking them difficult to maintain and clean.

Hence, fungus growth may develop in such channels and in that casefungus spores will quickly spread to all the rooms connected to thesystem. Furthermore, such systems often give rise to draught resultingin i.a. colds or acute or chronic sinus infections.

Small indoor fountains are known consisting of a tank and a water pump,the suction side of which being connected to the tank and the pressureside being connected to one or more nozzles for producing one or morewater jets having such a direction that the water falls back into thetank.

Such fountains produce a plashing or purling sound which is normallyperceived as pleasant and soothing and which, to a certain extent, maskssounds which are perceived as unpleasant.

A certain evaporation will occur when the water moves through the air,and to a certain extent the known fountains thus contribute to anincrease in the air humidity in the rooms in which they are located.

During the movement of the water some of the components of the room airmay be torn out by and optionally absorbed in the water, andconsequently a certain purification of the room air is obtained.

However, as the surface of the water jets and drops formed by suchfountains is normally small relative to the amount of air present, theair humidification and air purification obtained with the fountains arenormally insignificant.

Such indoor fountains suffer from the drawback that they should beplaced in a certain distance from other furniture because in case ofdraught there is a risk that the water jets or drops may spread to alarger area.

Thus, these indoor fountains are not suitable for arrangement of e.g.offices or shop premises.

As for the prior art technique, further reference is made to U.S. Pat.No. 4,747,538 which discloses a device of the type mentioned above. Inthis known device the wall consists of rectangular plates which areinclined such that the lower edge of one plate overlaps the upper edgeof the plate placed below, which in turn at its lower end overlaps theupper edge of the plate placed below. According to this prior arttechnique the means for forming the curtain-like stream of water areembodied as a row of holes or a slit in a trough into which water ispumped.

The row of holes or the slit is located proximate to the front of theupper edge of the upper plate and in such a manner that the outflowingwater immediately hits the plate in question and subsequently flows downalong the front of the plate, then immediately down onto the subsequentplate for finally to be caught into the collecting tank. In this caseonly one side of said water stream is available for air purification andair humidification.

DE-A-2743713 describes a device for improving indoor air environmentwhich comprises a vertical glass plate and a water overflow located atthe upper edge of said glass plate, said water overflow creating astream of water flowing down from the upper edge of the glass plate incontact with said glass plate.

DE-B-2534524 discloses an air humidifier comprising a structure havingvertically spaced projections of such a shape that water supplied to theupper projection will flow down over the underlying projections in theform of relatively narrow streams in a cascade-like manner.

The object of the present invention is to obtain a more efficient airhumidification and air purification than obtainable with the prior artdevices.

This object is obtained with the device according to the invention,which device is characterized in that the plate element comprises waterdischarge means located at the upper edge of said plate element andextending over the full width thereof, said water discharge means beinglocated at such a distance from the front side of the plate element thatboth sides of the curtain-like water stream formed by said waterdischarge means are in contact with the surrounding air.

The invention is based on the discovery that by providing waterdischarge means generating a curtain-like stream of water extending overthe full width of the wall and spaced from said plate element, thesurrounding air will be exposed to a much larger water surface than inthe prior art devices.

As both air humidification and air purification are proportional to theabove mentioned contact area, it is thus possible to obtain asignificantly more effective air humidification and air purificationthan with the known indoor fountains.

The plate element may consist of a single plate but is preferably madeup of two plates forming a space between them, the lower end of saidspace being connected to the water pump and the upper end thereof beingconnected to the water discharge means at the top.

It is preferred to provide a curtain-like stream of water having thesame width from the upper end to the lower end of the plate element.However, in practice it has been found difficult to obtain such astream. If e.g. the water is allowed to flow out over the upper edge ofthe plate element in its full width, the water curtain will have thesame width as the plate element at the beginning, but the width willrapidly decrease which is unfortunate in case where the largest possiblecontact area is desired. Esthetic points of view and consideration forthe generation of sound may also render it desirable to avoid such adecrease in the width of the water stream and to maintain or reestablishthe original width.

This can e.g. be obtained by arranging the plate element in such amanner that the fall of the water is divided into several steps so thata free-falling curtain-like stream of water having the original width isreestablished after each step.

Another possibility is to construct the upper edge of the plate elementin a manner so as to form a row of relatively small streams of water.The width of such streams will also decrease but not to the same extentas a stream of full width. The divisional streams formed will togetherform a stream having a free-falling curtain-like character.

The plate element expediently consists of one or more transparentplates. If the plate element consists of two plate connected along theside edges so as to form a chamber there between for the supply of waterto the upper edge of the plate element, the front plate is preferablytransparent. Thus it becomes possible to produce special visual effects.Air bobbles may e.g. be blow out at the lower end of the chamber, whichbobbles, in that case, will move up through said chamber and produce aspectacular visual impression.

The plate element is expediently constructed with an outwardly extendinglip at the upper edge of the element for forming the free-fallingcurtain-like stream of water in short distance from the plate element.

The lip may extend over the full width of the plate element but it mayalso be divided into sections to produce several streams of water.

The lip should preferably be integrated with a tank or a groove whichallows the introduced water to settle before flowing over the drip.

The stream of water can fall freely from the upper edge of the device tothe collecting tank, but often the free fall may advantageously takeplace in several steps. By allowing the water to move step by step downtowards the collecting tank, the water movement is delayed and thecirculating amount of water can be reduced accordingly. Furthermore, theabove mentioned problem regarding the reduction in the width of thecurtain-like stream of water in the fall direction is reduced. Last butnot least interruptions in the free fall will increase the contactbetween air and water which increases the air humidification and the airpurification and produces a greater sound effect.

If the water is desired to fall freely in steps, the plate element ispreferably constructed in such a manner that the water from a lip at theupper edge of the element falls down like a curtain to a groove or atank located a distance down the plate and constructed in a manner so asto collect the water stream and to direct the water to a lip from whichit falls yet another distance down the plate until it is collected by afurther tank or groove, etc. Said tanks or grooves may be of differentshape and extension thereby allowing varying stream patterns in the falldirection to be produced.

In a preferred embodiment of the device according to the invention oneor more of said tanks or grooves have a rounded form so as to deflectthe stream of water and direct it upwards and optionally towards ashield or the like which prevents the water from splashing outside thecollecting tank at the lower end of the plate element. By placing suchtanks or grooves at various levels the decreasing energy of the watercan be used for prolonging the route of the water stream from the upperedge of the plate element to the collecting tank at its lower end, andthis causes a significant increase in the area and of the time in whichwater and room air are in mutual contact resulting in an improved airhumidification and air purification.

As mentioned, the water collecting tank serves to collect the fallingstream of water so that it can be directed back to the water pump.Optionally the tank may be filled with elements, such a beach stones,which interrupt the stream of water, thereby increasing the contact areabetween water and air. A particularly large contact area is obtained byusing specially shaped elements, such as tubular pieces havingsubstantially the same height and diameter or small saddle shapedelements, instead of round elements. Such types of elements, which areused as fillings in distillation columns and gas scrubbers, are e.g.made of metal, ceramics or plastics.

In the case where a strong purling sound is desired, collecting tankshaving a large free surface are preferably used. The collecting tankshould have a size allowing it to hold the entire amount of water usedin the device, because in case of pump stop, e.g. in connection withelectric power failure, the water is collected in the collecting tank.

One or more lamps may be incorporated into the collecting tank forilluminating the front of the plate element or other parts of the deviceand thereby contributing to the production of a conspicuous estheticeffect.

The water pump may be located in the collecting tank proper but ispreferably mounted in a compartment located below the tank. The devicemay also comprise a filter and measuring and regulating equipmentlocated in the same compartment as the pump or in separate compartmentsbelow the collecting tank.

The filter used is preferably a mechanical filter but other filters mayalso advantageously be incorporated for treatment and purification ofthe water in the device. For instance charcoal filters may be used forremoving dissolved organic substances, e.g. toxic solvents fromconstruction materials, such as paint and lacquers, binders in carpetsand joint mortars. Furthermore, by means of such filters substancesderiving from tobacco smoking in the room can be absorbed to the extentof which such substances are absorbed in water.

In order to keep the device clean it is an advantage if the circulatingwater is free of dissolved salts. Distilled or ion-exchanged water canbe used. The same kind of water should be used for supplement water tocompensate for loses due to evaporation. In large plants where it may benecessary to supplement the water with normal tap water the device maybe expediently provided with a built-in deionisation cartridge which canbe replaced with a regenerated cartridge at regular intervals.

It is also possible to add desired substances to the water, e.g.substances emitting a faintly pleasant odour, thereby increasing theimpression of the environment-improving effect of the device. Ifdesired, substances having a recognized positive effect on the organism,e.g. substances facilitating breathing, may also be added to the water.

As mentioned above the means for directing the water to the upper end ofthe plate element may consists of a chamber formed between twosubstantially vertical plates. Thus, in such a plate element the waterwill flow up within the space between the plates and at the upper edgeflow out of the chamber and move like a free-falling curtain-like streamdown along at least one side of the element. Said construction may e.g.consist of a 8 mm acrylic plates glued together with a frame on threesides in a manner so as to form a chamber having an internal depth of10-50 mm and a great extension in both the width and height. The meansfor transporting the water to the upper end of the plate element mayalso consist of tube means placed at one or both sides of a plateelement. In a further embodiment said means consist of half tubessecured to the plate element.

In a particular embodiment of the device according to the invention theplate element in the form of an acrylic plate is suspended from a wall.At the bottom the plate has a collecting tank formed by bending of thelower edge of the plate. In the collecting tank a small submerged pumpmay be located which pumps water up into a top tank located at the upperedge of the plate and formed by bending of same via a duct formed by ahalf tube located at either side of the acrylic plate. The top tank maybe provided with holes or slits through which the water can flow andform a free-falling curtain-like stream of water.

The components of the device should be water resistant and preferably bemade from materials which are easy to keep clean and cleanse. Examplesof such materials are plastic materials, in particular plexi glass,glas, ceramics, marble, stainless steel and other metals.

In order to increase the hygiene the surfaces of the components of thedevice can be modified with coatings making them smoother, soilrepellent, or being bactericide.

As mentioned above the device according to the invention should alsogive a pleasant sound experience and especially a sound or purlingwater. Such a sound partly evokes associations of a nature experienceand to a large extent will partly be able to mask disturbing soundsgenerated in the room without acting disturbing itself. At a sound levelof 30-40 dB a wide-spectrum sound ("white noise") will make itimpossible to understand conversations carried on a greater distancefrom the listener who, therefore, "unconsciously" ceases to try tofollow the conversation and therefore resigns himself.

The device according to the invention aims at providing such awide-spectrum sound which allows a desired sound picture to be producedby varying the amount of water, the falling height, the water depth inthe collecting tank, etc.

If desired, the sound picture thus produced can be supplemented orreinforced electronically.

In this connection it may be desirable to supplement the device withmeans for controlling its function depending on the noise picture in theroom in which it is used.

As mentioned the device according to the invention serves i.a. toregulate the air humidity in the room in which it is placed. This canpartly be effected by discharging moisture to dry air or by absorbingwater from moist air. Such a discharge/absorption of moisture can beaffected by means of the temperature of the circulating water, and hencethe device is preferably provided with heating and/or cooling units.

The improvement of the indoor air-environment obtained with the deviceaccording to the invention i.a. also manifests itself in that thenuisances caused by static electrical charging are reduced.

In order to reduce or eliminate a tendency for some of the water to falloutside the collecting tank due to air currents in the room in which thedevice is used, tearring out water drops from the stream of water and inparticular from the lower end of the same, a further embodiment of theinvention comprises an inclined shield at the lower half of the plateelement, said shield extending upwardly and outwardly from the plateelement, the lower edge of said shield being placed relative to theplate element so as to form a relatively narrow slit between the twoelements. This shield effectively prevents water splash, andsurprisingly it has been found to produce simultaneously a significantincrease in the air circulation and air humidification in the room inwhich the device is located.

The increased air circulation and air humidification are assumed to becaused by the fact that the water, which flows sown into the abovementioned slit and which, due to the position of the shield at the lowerend of the plate element, has a significant speed of falling, carriesalong a considerable amount of air. Thus, it has been found that use ofthe device according to the invention generates a horizontal air streamhaving a speed of 0.6-1.0 m/sec. in the space in front of said slit.

The outflowing air has a considerable content of water drops whichincreases the air humidification.

In order to prevent said water drops from falling down on the floor infront of the collecting tank, the tank may be provided with means fordirecting the air stream in upwards direction before the air passesoutside the tank.

In an embodiment of the device according to the invention the abovementioned air-entrainment can be adjusted with the shield arrangedpivotably about a horizontal axis. By turning the shield the width ofsaid slit and thus the projection of the shield from the plate elementcan be regulated as desired.

In a further preferred embodiment of the invention the device has anequalizing tank located at the upper end of the plate element which, viaan overflow, is connected to a liquid distribution tank located at thefront of the element for producing the free-falling curtain-like waterstream. Said liquid distribution tank preferably has a row of holes atthe bottom which are so shaped as to form a curtain-like stream of watertogether.

The presence of said equalizing tank at the upper end of the plateelement makes it possible to reduce irregularities in the water streamfrom the water pump before the water reaches the liquid distributiontank so as to maintain a substantially constant water level therein.Thus, the curtain-like stream of water, which e.g. is formed by the rowof holes at the bottom of the liquid distribution tank, is maintainedrelatively constant.

The pump tube preferably debouches into the bottom of the equalizingtank and in order to moderate fluctuations in the stream of water in thepump tube, a plate is preferably mounted above the upper end of the pumptube for equalization of the liquid stream from the pump.

The overflow between the liquid equalizing tank and the liquiddistribution tank preferably comprises a plate provided with a row ofparallel, vertical incisions of a suitable depth. Said incisions providea uniform flow of water to the distribution tank even in case of anunprecise horizontal position of the overflow plate.

The described embodiment of the device according to the invention may beprovided with an adjustable guiding plate mounted in such a manner thatit extends downwards at an inclined angle into the space below the holesin the distribution tank. A suitable displacement of the guiding platein the direction towards or away from the plate element produces a freefalling curtain-like stream of water in a desired distance therefrom.The plate is preferably adjusted by regulating screws pivotably mountedin holders attached to plates extending from the vertical side edges ofthe plate element.

Preferably, two filters are mounted on the suction side of the pump,i.a. a coarse filter and a fine filter.

The coarse filter, e.g. in the form of a screen plate, is preferablylocated above the orifice of the suction tube of the pump in thecollecting tank. This filter serves to separate coarse particles.

The other filter, which may be a combined mechanical and chemicalfilter, is preferably located between the coarse filter and the pump.

The water collecting tank may be divided into an upper and a lowerchamber by a perforated horizontal plate onto which a layer of naturalstones or other ornamental objects may be placed.

In this embodiment the plate element preferably consists of atransparent plate of plastic, the upper edge of said plate optionallybeing bent and provided with the above mentioned parallel incisions.Likewise, the lower end of the plastic plate may be bent and preferablythe lower edge is located proximate to a source of light, e.g. afluorescent tube.

The light emitted from said light source will make the entire plateluminous and thereby increase the ornamental effect of the device.

The invention will now be described in further detail with reference tothe drawing in which

FIG. 1 is a perspective view of a preferred embodiment of the deviceaccording to the invention,

FIG. 2 is a vertical, longitudinal sectional view of the device as shownin FIG. 1,

FIG. 3 is a vertical cross sectional view of the device as shown in FIG.1,

FIG. 4 shows a preferred other embodiment of the device according to theinvention in perspective view,

FIG. 5 shows the device according to FIG. 4 in a vertical sectionalview, and

FIG. 6 and 7 show two detailed views of the lower part of the sheetelement of two particularly preferred embodiments of the deviceaccording to the other embodiment of the invention.

The drawing shows a box 1 having a base 2 which is intended to beloosely placed on a floor. The box 1 is divided into three chambers 3, 4and 5, a water pump 6 having an outlet tube 7 and an inlet tube 8 beingplaced in one of the chambers 4.

The other two chambers are intended for holding auxiliary equipment,such as filter, measuring and regulating equipment. The inlet tube 8 isconnected to a water collecting tank 9 in which a vertical, hollow sheetelement is located, said element consisting of a front plate 10 and aback plate 11 and two side plates 12 connecting the front plate 10 andthe back plate 11 at their side edges. Thus, a chamber 13 is formedhaving a hole 14 at the bottom connected to the outlet tube 7 of thepump 6, and an opening 15 at the top having a drip 16. The device alsocomprises a chamber 18 located behind the hollow sheet element, which issuitable e.g. as a plant box.

As will appear from FIG. 1 the device shown can provide a curtain-likewater stream 17 which falls down towards the tank 9 in a short distancefrom the front plate 10 and produces a water splash in the tank.

The movement of the water down along the front plate 10 will partlycause an evaporation of water and partly an absorption orair-entrainment of substances contained in the room air, therebycreating an improvement in indoor air-environment.

After the water has optionally been cleaned by filtration the pump 6again directs it up to the chamber 13 in order that it can be carriedover the drip 16 again.

In FIG. 4 and FIG. 5 101 designates a plastic plate which at the upperend has a first bending 102 and at the lower end a second bending 103.The plate 101 is located in a box 104 having a bottom 105, two end walls106 extending to the upper end of the plate 101, as well as a frontplate 107 and a back plate 108. The box 104 comprises two liquidchambers 109 and 110 having a perforated plate 111 mounted between them.In a lower chamber 112 in the box 104 a water pump 113 is located whichon the suction side is connected to the liquid chamber 110 via a tube114. The orifice of the tube 14 which debouches into the liquid chamber110 is covered by a screen plate 115. A filter 116 is furthermoremounted in the tube 114. The pressure side of the pump 113 is connectedto an equilizing tank 118 via a tube 117, said tube debouching into thebottom of the tank 118. In a short distance above the tube orifice abaffle plate 119 is mounted. Spaced vertical incisions 120 are formed inthe bended part 102 of the plate 101.

Furthermore, at the upper end of the plate 101 a water distribution tank121 is located having a tapered bottom 122 in which a row of closelyspaced holes are formed.

An adjustable inclined guiding plate 124 is mounted below the bottom 122of the tank 121. The position of the guiding plate 124 is adjusted bymeans of regulating screws 125 mounted in holders 126 located at the endplates 106.

The device shown further comprises an adjustable splash shield 130 whichis pivotably arranged about a horizontal axis, the angle position ofwhich can be locked by means of regulating screws 131 and 132.

The splash shield 130 is mounted in such a manner that a relativelynarrow slit 133 is formed between the lower edge of the shield 130 andthe plate 101.

Finally, the device comprises a light source 134 located at the edge ofthe bending 103 on the plate 101.

The device shown operates in the following manner:

On starting the pump 113 water is pumped from the chamber 110 throughthe screen plate 115, the filter 116, the pump 113 and the tube 117 tothe tank 118. From the tank 118 the water flows through the incisions120 in the bending 102 to the distribution tank 121. The water flowsfrom the bottom of the tank 121 through the holes 123 down towards theguiding plate 124. Depending on the position of the latter the watermoves down towards the tank 104 as a curtain-like stream in a shortdistance from the plate 101.

During the downward movement the water reaches the space between theshield 130 and the plate 101 and is thereby forced to pass through theslit 133. Having passes the slit 133 the water flows down into thechamber 109 and proceeds through the perforated plate 111 down into thechamber 110.

In the space below the shield 130 a horizontal air stream is generatedas indicated by the arrow 135.

In operating the device described above, impurities in the air areentrained by the falling stream of water as it appears from the depositsformed on the filters 115 and 116.

The embodiment shown in FIG. 6 comprises in addition to the plate 101and the shield 130 a guiding plate 136 having the lower edge locatedclose to the water surface 137 in a tank 138. The presence of saidguiding plate 136 causes water drops, which are carried along with theair stream indicated by the arrow 139, to be directed upwards therebyconsiderably reducing the risk of the drops falling outside the tank138.

In the embodiment shown in FIG. 7 the tank 138 has a perforated top wall140 which allows the passage of air and at the same time serves as abaffle plate for water drops contained in an air stream indicated by thearrow 141.

We claim:
 1. A device for improving indoor air-environment, and inparticular for providing a suitable air humidification and absorption ofundesired substances as well as creating a pleasant sight and soundenvironment, which device comprises a plate element (10; 101) and awater pump (6; 113) connected to water discharge means (16; 121) forforming a curtain-like stream of water (17) at the upper end of theplate element, and a tank (9; 104) located at the lower end of the plateelement for collecting and recirculating the water to the water pump(9), wherein the water discharge means (16; 121) are located at such adistance from the front side of the plate element (10; 101) that bothsides of the curtain-like water stream formed by said water dischargemeans (16; 121) are in contact with the surrounding air, and the devicefurther comprises an inclined shield (130) extending upwardly andoutwardly from the plate element (101) and being located at the lowerhalf of the plate element (101), the lower edge of said shield beinglocated at such a distance from said plate element that a narrow slit isformed between the shield (130) and the plate element (101).
 2. A deviceaccording to claim 1 wherein the plate element (10; 101) is composed ofplates (10; 11) forming a space (13) therebetween, the lower end of saidspace being connected with the water pump (6; 113) and the upper endthereof communicating with the water discharge means (16; 121).
 3. Adevice according to claim 1 wherein the tank (104) is divided into anupper and a lower chamber by a perforated horizontal plate (111).
 4. Adevice according to claim 1 wherein the shield (130) is arrangedpivotably about a horizontal axis.
 5. A device according to claim 1wherein the tank (104) comprises means (140) for directing an air streamgenerated below the slit in upward direction before said air flowsoutside the tank (138).
 6. A device according to claim 1 wherein theplate element (101) comprises a transparent plastic plate and that alight source (134) is placed at the lower edge of said plate.
 7. Adevice according to claim 1 wherein comprising an equalizing tank (118)located at the upper end of the plate element (101) which tank (118),via an overflow (102), is connected to a liquid distribution tank (121)located at the front of the plate element (101).
 8. A device accordingto claim 7 wherein the bottom of the liquid distribution tank (121)comprises a row of closely spaced holes (123) located spaced from thefront of the plate element (101).
 9. A device according to claim 7wherein the overflow (102) comprises a plate (102) having a row ofparallel, vertical incisions (120).
 10. A device according to claim 7comprising a pump tube (117) which debouches into the bottom of theequalizing tank (118), wherein a plate (119) for equalization of theliquid flow from the water pump (113) is located above the upper end ofthe pump tube (117).